The present invention relates to a dot-matrix display device such as an organic electroluminescence (EL) display device, a method of driving the display device, and a driver circuit of the display device.
FIG. 29 is a circuit diagram showing a conventional organic EL display device. As shown in FIG. 29, the conventional display device has n common lines (namely, scan lines) COM1 to COMn arranged in rows, m data lines SEG1 to SEGm arranged in columns, and n×m EL elements PE1,1 to PEm,n that are disposed at the intersections of the common lines and the data lines. In addition, the display device has switching elements SWC1 to SWCn which connect the common lines COM1 to COMn to either the ground-voltage portion GND (voltage VG) or the high-voltage portion 20 for common lines (common line power-supply voltage VC), switching elements SWS1 to SWSm which connect the data lines SEG1 to SEGm to either the ground-voltage portion GND (voltage VG) or the high-voltage portion 30 for data lines (data-line power-supply voltage VS), and a drive control circuit 10 which controls the switching elements SWC1 to SWCn and SWS1 to SWSm. In FIG. 29, a reference 11 denotes a constant-current output circuit.
FIG. 30 is a waveform diagram showing the operation of the display device of FIG. 29. As shown in FIG. 30, the display device selects the common lines one after another, brings the selected common line to the ground voltage VG, and brings the non-selected common lines to the common line power-supply voltage VC (reverse-bias voltage), during each display period P2 included in each scan period P0. During the display period P2, selected data lines are brought to the data-line power-supply voltage VS, and non-selected data lines are brought to the ground voltage VG, on the basis of the signal input to the drive control circuit 10. During the display period P2 time point t2 to t3) shown in FIG. 30, the data line SEG1 is selected, so that the current I1 flows through the EL element PE1,1, thereby bringing the EL element PE1,1 to the light-emitting state, as shown in FIG. 29.
In addition, as shown in FIG. 30, the display device brings all the common lines COM1 to COMn and data lines SEG1 to SEGm to the ground voltage VG during the discharge period P1 included in the scan period P0. During the discharge period P1, the charge stored in the common lines COM1 to COMn and data lines SEG1 to SEGm are discharged.
When bringing the EL element PE1,1 into the displaying state, for instance, the conventional display device as described above forms a current path passing the EL element PE1,1 (the high-voltage portion 30 for data lines, the switching element SWS1, the data line SEG1, the selected EL element PE1,1, the common line COM1, the switching element SWC1, and the ground-voltage portion GND in this order). In this type of display device, however, a current path passing a non-light-emitting EL element (for instance, the high-voltage portion 30 for data lines, the switching element SWS1, the data line SEG1, the non-selected EL elements PE1,2 to PE1,n, the non-selected common lines COM2 to COMn, the switching elements SWC2 to SWCn, and the ground-voltage portion GND in this order), through which no current should flow, is instantaneously formed at a time point t1 or t2, for instance, and a shoot-through current (that is, “shoot-through current via non-selected EL elements”) flows, resulting in a waste of power. Moreover, if the switching elements SWC1 to SWCn are configured as CMOS circuits, a current path passing a CMOS circuit (the high-voltage portion 20 for common lines, the PMOS transistor, the NMOS transistor, and the ground-voltage portion GND in this order) is instantaneously formed at a reversal of the CMOS circuit, causing a shoot-through current (that is, “shoot-through current of CMOS circuit”) to flow, resulting in a waste of power.